Molecular Genetics

Question 1

What did Miescher discover?

Answer 1

He discovered nucleic acid which is rich in nitrogen and phosphorus.

Question 2

What did Levene discover?

Answer 2

He discovered that there are 2 different types of nucleic acids, DNA and RNA.

Question 3

What did Thomas Hunt Morgan discover?

Answer 3

He confirmed that genes are stored in chromosomes through the fruit fly experiment.

Question 4

What was Griffith’s experiment
(Transforming Principle)

Answer 4

He found that hereditary information passed from dead bacterial cells to live bacterial cells. To find this, he gave a mixture of heat killed pathogenic and live non-pathogenic strains of S. pneumonia to a mouse and it was killed. In conclusion something must have transformed the living non-pathogenic bacteria to make them disease causing. The molecule that was responsible for this was still unclear…

Question 5

What did Avery, MacLeod, and M. McCarty do?

Answer 5

They conducted experiments that provided strong evidence that DNA was responsible for the transformations.

Question 6

What did Hershey and Chase prove?

Answer 6

They proved through radioactive labelling that DNA was hereditary.

Question 7

What are DNA and RNA made of?

Answer 7

Nucleotides

Question 8

What are the four nucleotides?

Answer 8

Adenine
Guanine
Cytosine
Thymine

Question 9

What are the purines as opposed to pyrimidines?

Answer 9

A purine has a single ring while a pyrimidine has 2.

Question 10

What are the two purines?

Answer 10

Adenine and Guanine.

Question 11

What are the two pyrimidines?

Answer 11

Cytosine and Thymine.

Question 12

What is chargaff’s rule?

Answer 12

A and T are found in pairs (A=T)
C and G are found in pairs (C=G)
(A+G=C+T)

Question 13

What did R Franklin do?

Answer 13

He used X-ray photography to see the double helix structure of DNA.

Question 14

What did Watson and Crick do?

Answer 14

First to produce a 3-D double helix model of DNA.

Question 15

What are the sides of double helix DNA made of? (What is the backbone?)

Answer 15

It is made of sugar and phosphate.

Question 16

Where do the nucleotides connect to the backbone of DNA?

Answer 16

They connect to the sugar part of the backbone.

Question 17

What are the rungs extending inwards from the backbone that connect to the nucleotides made of?

Answer 17

Nitrogen bases.

Question 18

Are both sides of the double helix identical, why or why not?

Answer 18

They are not identical because the two sides are complimentary as suggested by Chargaff’s rule.

Question 19

Similarities/differences between DNA and RNA?

Answer 19

DNA
- double helix
- mostly in nucleus
- made of deoxyribose
- has bases A, G, C, and T
- only one type

RNA
- single stranded
- found throughout the cell
- sugar is ribose
- bases are A, G, C, and U
- (mRNA) (tRNA)(rRNA)

Question 20

What kind of DNA is only inherited from the mother?

Answer 20

mtDNA (contained within the ova)

Question 21

What does dogma mean?

Answer 21

DNA only flows in one direction, from DNA to RNA to protein.

Question 22

What is meant by semi-conservative replication?

Answer 22

The term semi-conservative replication refers to the process of DNA replication that only uses one strand of nucleotides to make the new DNA identical to the old DNA. The process is essentially half-old, half-new.

Question 23

What are the processes of DNA replication in order?

Answer 23

Initiation, Elongation, and Termination.

Question 24

What happens during initiation of DNA replication?

Answer 24

Helicases bind to the DNA and unravel a small segment by breaking the hydrogen bonds which hold complimentary pairs together. Each unwound area is called a replication bubble and at the end of each bubble is a “Y” or a replication fork.

Question 25

What happens in the Elongation segment of replication?

Answer 25

Primase makes RNA primer which serves as a starting point for the attachment of nucleotides. DNA primerase attaches the complimentary nucleotides onto the parent strand. One strand is elongated continually in the 5’ to 3’ direction. The other strand is elongated in small fragments (Okazaki fragments). DNA ligase fuses DNA fragments together and adds a sugar-phosphate backbone.

Question 26

What happens during the termination phase of replication?

Answer 26

The two DNA molecules desperate and rewind automatically.

Question 27

What does helicase do?

Answer 27

Cleaves and unwinds DNA

Question 28

What does primase do?

Answer 28

Synthesizes primer to begin elongation process.

Question 29

What does DNA polymerase do?

Answer 29

Adds new nucleotides from 5’ to 3’

Question 30

What does DNA ligase do?

Answer 30

Splices together Ozarki fragments of lagging strand.

Question 31

What is a codon?

Answer 31

A group of 3 based on a gene.

Question 32

Place a codon, a nucleotide, and a gene in order from smallest to largest

Answer 32

Nucleotide, codon, gene

Question 33

Where do new nucleotides attach for the production of RNA?

Answer 33

Nucleotides attach to the 3 prime side of DNA to produce RNA.

Question 34

What are the three characteristics of genetic code?

Answer 34

It is redundant (more than one codon can code for an amino acid)
It is continuous (reads without spaces, punctuation, or overlap)
It is universal (all organisms use the same code)

Question 35

How is information moved from DNA to proteins?

Answer 35

DNA is made into RNA through transcription in the nucleus and sent out to the cytoplasm.

Question 36

What does mRNA do?

Answer 36

Moves out of the nucleus and takes the genetic information to the ribosomes in the cytoplasm. This is a messenger.

Question 37

What happens during transcription?

Answer 37

Double stranded DNA is copied into single stranded mRNA.